# Timken 2MM9303WI TUM Super Precision Angular Contact Ball Bearing, Triplex Medium Preload, ABEC 7 - MROSupply.com

***Timken 2MM9303WI TUM super precision angular contact ball bearing, triplex set with medium preload (TUM), ABEC 7 (P4S) precision. Designed for high-rigidity machine tool spindles, providing accurate rotational performance under combined radial and axial loads.***



## Product details:

- Catalog number: 2MM9303WI TUM
- SKU: 5115423
- Call for Pricing - 888-671-2883
- Shipping: ***FREE SHIPPING***  ON ORDERS OVER $100
- Typically Ships in: 1 day
- Brand: [Timken](https://www.mrosupply.com/brands/timken/)
- Category: 
    - [Single Row Angular Contact Bearings](htts://www.mrosupply.com/bearings/ball-bearings/angular-contact-ball-bearings/single-row-angular-contact-bearings/)
    - [Angular Contact Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/angular-contact-ball-bearings/)
    - [Ball Bearings](htts://www.mrosupply.com/bearings/ball-bearings/)
    - [Bearings](htts://www.mrosupply.com/bearings/)
- Unit of measure: each
- Weight: 0.119 lb
- Returns: Yes


## Product images:
- https://static.mrosupply.com/images/noimage.webp


## Product attributes;

  
- 0.2756 in C0 - Static Radial Rating (per row): 2800 N
  

  
- 0.790 in Limiting Speed (Grease) (per row): 50100 rpm Limiting speed (oil):100200 rpm Manufacturing part number:2MM9303WI TUM O.D. (in):30 mm 1.1811 Outer ring backing diameter:27.5 mm
  

  
- 0.8268 in World part number: 71903C-T-P4S-TUM
  

  
- 1.080 in Rows per set: Triplex Total width:21 mm
  

  
- 1020 lbf Cage type: CR - Phenolic Outer Land Riding Cage Contact angle:15 Design units:Metric Inner ring backing diameter:20.0 mm
  

  
- 630 lbf C1 ISO - Dynamic Radial Rating (per row): 4520 N
  

  
- Ball type: Steel Bearing width:7 mm
  

  
- Ball Type: STEEL
  

  
- Bearing Width: 7 mm 0.2756 in
  

  
- Bore: 17 mm
  

  
- C1 ISO - Dynamic Radial Rating (per row): 4520 N 1020 lbf
  

  
- Cage Type: CPhenolic Outer Land Riding Cage
  

  
- Contact Angle: 15 º
  

  
- Design Units: Metric
  

  
- DOuter Ring Backing Diameter: 27.5 mm 1.080 in
  

  
- Dynamic Radial Rating (per row): 4970 N 1120 lbf
  

  
- I.D.: 17 mm
  

  
- Inner Ring 'To Clear' Radius: 0.30 mm 0.012 in
  

  
- Inner Ring Backing Diameter: 20.0 mm 0.790 in
  

  
- Limiting Speed (Grease) (per row): 50100 rpm
  

  
- Limiting Speed (Oil): 100200 rpm
  

  
- Manufacturing Part Number: 2MM9303WI TUM
  

  
- Outer Diameter: 30 mm 1.1811 in
  

  
- Outer Ring 'To Clear' Radius: 0.3 mm 0.012 in
  

  
- Rows per Set: Triplex
  

  
- Static Radial Rating (per row): 2800 N 630 lbf
  

  
- Total Width: 21 mm 0.8268 in
  

  
- World Part Number: 71903C-T-P4S-TUM
  
## Product documents / software:

- [Catalog](https://documents.mrosupply.com/product_documents/50/60/5060627/Machine-Tool-Applications-Catalog_R9rBZA3.pdf)

## Product's reviews:
- Best company to buy from - I always buy from MRO is a very reliable company to work with




## FAQ:

- How do I choose the right type of bearing for my application?: Start with the load and how it’s applied. You need to know if you’re dealing with radial loads, axial loads, or a mix of both. Then look at speed, operating environment, and space constraints.
For example, ball bearings are great for high speed and lighter loads, while roller bearings handle heavier loads but usually at lower speeds. If there’s contamination, moisture, or heat involved, you may need sealed bearings or specific materials.
In most cases, the right choice comes down to matching load type, speed, and environment to the bearing design.


- What is the difference between deep groove and angular contact ball bearings?: Deep groove ball bearings are the most common type. They’re designed to handle mainly radial loads, but they can also take some axial load in both directions. They’re simple, versatile, and used in everything from motors to conveyors.
Angular contact ball bearings are built for combined loads, especially where there’s significant axial force in one direction. They’re often used in pairs and are common in higher precision or higher load applications like pumps and gearboxes.
If your load is mostly radial, go deep groove. If axial load matters more, angular contact is usually the better choice.